500 -calories until hours?

I weigh a couple pounds more than you. For me, standing for an hour burns about 120. Walking without a burden for an hour burns about 240. So 500 total in two hours sounds like it could be right.

But just keep in mind you probably would have burned about 100-150 in that two hours if you'd been completely sedentary.

HRMs measure heart rate. They do not measure calories burned.

The athletic science community has developed a number of calculations during aerobic exercise that can help calculate the number of calories burned during steady state aerobic exercise.

So, first, your HR has to be up above 50% of your max HR before the calculation begins to be accurate. I wasn't there while you were doing laundry, but I really doubt it was in that range.

I also doubt you were in a steady state of movement in that heart rate range for two straight hours.

Bottom line, no, it's not accurate.

I just bought a HRM and decided to wear it to get used to it... I've had it on for about two hours and it says i have burned 500 calcries. This is just doing housework. Laundry, vacuuming, sweeping, cooking, etc... Does this sound accurate? I weight 157 pounds....in 5'3

HRM is for steady elevated heartrate. Not for wearing it around all day. It's not going to be accurate at all for what you're doing.

^^ This ^^
HRM is a training aid for cardio not a daily activity monitor.